Hypodermic implant device

ABSTRACT

A hypodermic implant device, comprising a barrel; an upper piston segment engaged with an inner wall of the barrel; an axially aligned needle extendably distally out of the barrel for insertion into an object when the upper piston segment is moved distally within the body; a lower piston segment push rod in alignment with the needle, so that upon distal movement of the lower piston segment, the push rod moves distally through the needle expelling a releasable implant housed in the needle; and a means for retraction of the needle into a needle receptacle in the barrel.

CROSS REFERENCE TO A RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/301,271, filed Jun. 26, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of Use

[0003] The field of use for the hypodermic implant device described inthis specification is for injecting implants into living or non-livingorganisms or things, such as inanimate articles and materials. Mostoften the implant device will be used for injecting an implant intosubcutaneous tissues and blood vessels. The implant may be used fortracking and treatment of humans, animals, and plants. For purposes andillustration of an embodiment of the invention claimed in thisspecification, an application for the treatment of humans and animalswill be described in the “Summary of an Embodiment of the Invention,”the “Brief Description Of The Drawings”, and the “Detailed DescriptionAnd Operation Of The Invention” sections of this specification.

[0004] 2. Description of the Related Art

[0005] Hypodermic implant devices are on the market today. They are usedin clinical, surgical, and outdoor settings. However, the currentlymarketed hypodermic implant devices suffer from several shortcomings.Their extended needle poses a hazard of accidental needle sticks to thecaregiver, the patient, and researchers. These devices do not have anearly fail-safe method of self-destruction after use, thereby allowingpossible reuse and the concomitant transmission of disease. Disposal ofavailable implant device also poses risk of accidental needle sticks dueto the extension of the islet or needle portion of the used implantdevice. The exposed islet also necessitates the use of special disposalcontainers for sharp contaminated articles. Furthermore, currentlyavailable hypodermic implant devices rarely feature a safety mechanismfor locking the implant device to prevent accidentally expelling theimplant. The invention described in this specification solves theseneeds.

SUMMARY OF AN EMBODIMENT OF THE INVENTION

[0006] With the proliferation of many blood borne contagious diseases,such as AIDS and Ebola, the frequent use of hypodermic implant devicesposes a serious risk of infection. Many times, it is not possible todetermine for an extended period of time whether a caregiver orresearcher has been infected as a result of a needle sticks. The resultcan be actual infection with a sometimes-lethal blood borne pathogen ora prolonged period of anguish and worry only to discover that the useris not infected. Use of hypodermic implant devices pose significantrisks in the everyday clinical practice of medicine, whether the patientbe a human or some other specie of animal, and in the outdoorimplantation of animals for research, tracking, or identification.

[0007] It has long been recognized that the needle stick risk factorneeds to be controlled. Training and care while using hypodermic implantneedles is emphasized. But, this, in of itself, is not enough,considering the high probability of a needle stick and the disastrouslevel of damage to health that it can inflict upon both the patient andcaregiver.

[0008] It is common practice in the health care or research industry touse a hypodermic implant device only once and then to dispose of it in asafe manner. However, currently marketed implant devices are notdesigned to self-destruct after a single use, thereby posing a risk ofmultiple uses. The hypodermic implant device of the present invention isdesigned so that it can be used once, only. Retraction of the piston ofthe device of the present invention results in retraction of the needlethrough and out of the luer fitting on the distal end of the barrel. Thenozzle end of the needle then drops into a needle receptacle at thedistal end of the barrel of the implant device making it virtuallyimpossible to extend the needle outside the barrel. With the needletilted into the distal end of the receptacle, the needle issimultaneously disabled from further use and safely disposed of; therebyavoiding transmission of infections by accidental needle sticks.Furthermore, in the clinic, hospital, veterinarian office, and farm orother field settings, the disposal of the implant device is much saferand may require a less costly disposal method than the currently usedmethod of sharps disposal. The present invention features a normallyretracted needle. This alone reduces risk of accidental needle sticks,since the needle is not exposed until it is actually ready to beinjected into the target's tissue.

[0009] This invention also features a locking mechanism that preventsthe needle from accidental extension beyond the barrel of the implantdevice. Extension of the needle requires the user to deliberatelydepress a tab-like lock, which is integrally molded into the piston.Depression of the lock into a lock space in the piston allows the lockto clear the inside diameter of the barrel, the piston to travel inaxial alignment with and into the barrel, and extension of the needlebeyond the distal end of the barrel.

[0010] This “Summary of an Embodiment Of The Invention” sectiondescribes the invention configured for implantation into humans andanimals for purposes of illustration. It is to be understood that thisinvention may be used for myriad other applications.

BRIEF DESCRIPTION OF THE DRAWINGS OF AN EMBODIMENT OF THE INVENTION

[0011]FIG. 1 is a partial sectional view along a plane parallel to thelongitudinal axis of an embodiment of the hypodermic implant device withthe piston in the rest position.

[0012]FIG. 2 is a partial sectional view along a plane parallel to thelongitudinal axis of an embodiment of the hypodermic implant device withthe upper piston segment of the split piston in the full needleextension position.

[0013]FIG. 3 is a partial sectional view along a plane parallel to thelongitudinal axis of an embodiment of the hypodermic implant device withboth the upper and lower segments of the split piston in the implantinjection position.

[0014]FIG. 4 is partial sectional view along a plane parallel to thelongitudinal axis of an embodiment of the hypodermic implant device withthe upper and lower piston segments fully retracted with the needletilted into the needle receptacle for safe disposal and for selfdestruction of the implant injection device, thereby limiting the deviceto a single use.

[0015]FIG. 5 is a plan view of the proximal end of the barrel and thesplit piston of an embodiment of the hypodermic implant device of thepresent invention with an exemplar of user directions for extension ofthe needle and then for insertion of the implant.

[0016]FIG. 6 is an axial cross section view of the needle and itssupport plate of an embodiment of the hypodermic implant device of thepresent invention.

[0017]FIG. 7 is a plan view of the distal end of the needle supportplate of an embodiment of the hypodermic implant device of the presentinvention.

[0018]FIG. 8A is a longitudinal view of the upper piston segment with apre-load spring at its distal end of an embodiment of the hypodermicimplant device of the present invention.

[0019]FIG. 8B is a partial longitudinal view of the upper piston segmentis illustrating the distal end of the segment with a pre-load devicethat is an alternative to the pre-load spring illustrated in FIG. 8A.

[0020]FIG. 9 is a longitudinal view along the axis of the barrel of anembodiment of the hypodermic injection device of the present invention.

[0021]FIG. 10 is a longitudinal view of the lower piston segment of anembodiment of the hypodermic implant device of the present invention.

[0022] This “Brief Description of the Drawings of an Embodiment of theInvention” section describes an application for the treatment of humansand animals for illustration purposes only. It is to be understood thatthis invention may be used for myriad other applications.

DETAILED DESCRIPTION AND OPERATION OF AN EMBODIMENT OF THE INVENTION

[0023]FIGS. 1 through 4 show the basic structure, assembly, and mode ofoperation of hypodermic implant device 1 of the present invention. FIG.1 illustrates the initial state of device 1 when delivered, for example,in a sterile package to the user of implant device 1. Hypodermic device1 as illustrated in FIG. 1 is comprised of barrel 2, piston 3, needlereceptacle 4, lock 5, and needle 6. Barrel 2, piston 3, needlereceptacle 4, and needle 6 are in axial alignment with one another alongcentral axis 62. Piston 3 is split into two segments: upper pistonsegment 13 and lower piston segment 14. Needle 6 may be a stainlesssteel 300 Series, but any needle having a nozzle 20, a bore 22, and aninlet 21 may be suitable, depending upon the application. Piston 3 islocked in the position shown in FIG. 1 by locks 5. Locks 5, as shown inFIG. 1, are integrally molded into and is a part of piston 3. Locks 5are connected to upper and lower piston segments 13 and 14 by tabs 41.Piston 3 and barrel 2 are plastic molded elements, using conventionalplastic molding techniques. The types of plastics suitable for theimplant device 1 are, for example, polycarbonate and polypropylene.These plastics are commercially available and currently used in themanufacture of hypodermic implant devices. These types of materials aresufficiently impact resistance to withstand the normally encounteredforces and usage without sustaining damage. Substitute materials arealso readily available for manufacture of device 1 for use in especiallydemanding environments, such as the research laboratory, outdoors, or inconjunction with injecting lubricants, adhesives, and other solids. Whenlock 5 is in its normal molded position, it is raised above the outsidediameter of piston 3 and the inside diameter of barrel 2. In thisposition, the distal end of lock 5 engages with the proximal end ofbarrel 2, at the junction with barrel grip 8, to prevent piston 3 fromsliding into barrel 2 by an axial force on piston 3 in the direction ofthe distal end of barrel 2. The term distal is used to refer to needle 6end of hypodermic device 1 of the present invention. The term proximalis used to refer to the other end of device 1. Tab 51 is of a thicknessthat allows lock 5 to be relatively easily depressed by the user'sfinger when using implant device 1, yet thick enough that it will not beaccidentally depressed during normal shipping, handling, andmanipulation of device 1. In other words, it is of a thickness thatrequires a conscious effort to depress. Upon depression, lock 5 movesinto lock depression space 12. Space 12 is of sufficient depth that whenlock 5 is fully depressed it seats in space 12 with the upper surface oflock 5 at or below the outside diameter of piston 3, thereby allowingpiston 3 to slide into barrel 2 upon application of a distally directedforce on the piston. Since lock 5 is molded in the normally up position,i. e., at least the distal end of lock 5 is extended beyond the outsidediameter of piston 3, it has memory that returns it to the normally upposition when any downward force on lock 5 is relieved. The downwardforce is relieved when the users finger pressure ceases or when piston 3is pulled in a proximal direction relative to barrel 2 to the pointwhere the distal end of lock 5 extends beyond the inner wall of barrel2, thereby once again locking piston 3 so it cannot be extended intobarrel 2 without further downward pressure on lock 5. The surface oflock 5 adjacent the outer wall of piston 3 is curved on the same radiusas the outer wall of piston 3, which is the same radius as the innerwall of barrel 2. This allows for smooth travel of piston 3 into barrel2.

[0024] Piston 3 locking feature prevents accidental extension of needle6. If needle 6 is accidentally extended, it may be exposed to harmfulpathogens or other substances and be damaged by blunting, bending, orscraping forces occurring in the working environment. More importantly,the exposure of needle 6, except when it must be extended for injectionof an implant, increases the possibility of an accidental needle stick.Upon the occurrence of a needle stick, it is often not possible todetermine whether an infectious substance was on needle 6. The resultinguncertainty, and in the case of AIDS months or years of waiting, whetherthe person experiencing the needle stick has become infected, is oftenthe cause of untold anguish and disruption of the care giver's career.And, of course, the consequences of actual infection are often fatal andseriously life compromising during the period of sickness.

[0025] Upper and lower piston grip segments 15 and 16 provide anergonomic thumb seat 23 for the user's thumb to rest during movement ofpiston 3 into barrel 2. The dotted line drawn on piston grip 7 in FIG. 1is the depression, which forms the thumb seat 23.

[0026] Circumferentially placed around the outside periphery of piston 3are four longitudinal ribs 9. Ribs 9 provide structural strength topiston 3. Ribs 9 allow piston 3 to be molded using less material thanwould be used if piston 3 diameter were substantially equal to theinside diameter of barrel 2 completely around the piston's entirecircumference and along the piston's entire length. Additionally, theadded friction between the surface of the outside diameter of piston 3and the inside diameter of barrel 2, would require greater force to beapplied to piston 3 to move piston 3 distally into barrel 2. With onlyribs 9 providing contact with the inside surface of barrel 2, less forceis required for movement of piston 3. Barrel grip 8 provides the userwith a means to grip barrel 2 when depressing upper or lower pistonsegments 13 and 14 into barrel 2. The user's fingers grip the distalside of barrel grip 8 and the thumb depresses the respective upper orlower piston segment 13 or 14.

[0027] Piston rings 10 provide for circumferential support for piston 3within barrel 2. The periphery of upper faceplate segment 31 and lowerfaceplate segment 32 also function to provide circumferential support.The additional support and the added friction assists with the smoothand tight fitting movement of piston 3 within barrel 2. Since eachpiston ring 10 is relatively narrow, the added friction is not greatenough to require excessive force by the user to extend piston 3 intobarrel 2. A gasket between needle receptacle 4 and the interface betweenpiston 3 and barrel 2 is not needed for the hypodermic implant device 1,since there are no fluids in the device 1 as in a hypodermic injectiondevice.

[0028] Support plate 29 supports the proximal end of needle 6 withinbarrel 2. Bonding material 25 bonds needle 6 into support plate 29.Support plate 29 is positioned relative to upper face plate segment 44by pre-load spring 42, one end of which is seated in support platespring seat 43 and the other end seated in upper face plate segmentspring seat 44 as illustrated in FIGS. 1 through 4, 6, 8A, and 11.Needle receptacle 4 is formed in the distal interior end of barrel 2.The distal end of needle receptacle 4 terminates in luer sleeve 28 andthe proximal end terminates in the combination of support plate 29 andupper and lower faceplate segments 31 and 32.

[0029] Luer needle guide 24 supports the distal end of needle 6. Luerneedle guide 24 extends through a portion of luer sleeve 28 as alsoshown in FIG. 9. Support plate plug 35 mates with support plate plugcavity 47 when upper piston segment 13 is in its most distal position.Support plate plug cavity 47 comprises support plate guide way 57 andsupport plate needle pilot 36 both of which axially connect to formsupport plate plug cavity 47, as illustrated in FIG. 9. End cap 18 andseal 48 are inserted into end cap cavity 17. End cap 18 and seal 48 mayeither be friction fitted or bonded into end cap cavity 17. End cap 18may be made of the same material as which the hypodermic implant device1 barrel 2 and piston 3 are made or other suitable material that willallow end cap 18 to nonreleasably fit into end cap cavity 17. End cap 18fixedly retains seal 48. Seal 48 can be made of the same or similarmaterial as a septum used on a vial of an injectable drug. The septum ofa drug vial allows the needle of a hypodermic injection device to beinserted through it for the purpose of withdrawing the medical fluid inthe vial up into the injection device. Upon removal of all or a portionof the fluid from the vial, the septum seals itself, thereby maintainingthe fluid safe from the environment and exposure to contamination. Inimplant injection device 1, seal 48 is a barrier that maintains needle 6and implant 11 free from contaminants while they are in needlereceptacle 4. But, it is a barrier that is easily penetrated by needle 6when the user extends upper piston segment 13 in a distal direction tofully extend needle 6. Seal 48 is usually a silicone rubber material.

[0030] Needle guide 40 of end cap 18 and luer needle guide 24 arealigned with the central axis 62 of barrel 2. End cap 18 is provisionedwith end cap needle pilot 50 for guiding needle 6 into end cap needleguide 40, as illustrated in FIG. 9. The combination of support plateplug cavity 57, support plate plug cavity 47, needle pilot 36, leurneedle guide 24, seal 48 after perforation by extension of needle 6, endcap needle pilot 50, and needle guide-way 40 is referred to in thisspecification as needle guide-way 60.

[0031]FIG. 2 illustrates hypodermic device 1 with needle 6 in the fullyextended position. Needle 6 is positioned in the fully extended positionby pushing upper piston segment 13 in the distal direction by usingthumb pressure on upper piston grip segment 15 while grasping one orboth barrel grips 8. Upper piston segment 13 and lower piston segment 14are matingly and slidably engaged along their longitudinal interface bychannel slide 45 and channel key 46, respectively. Channel slide 45,shown in FIG. 8A, may have a hemispherical cross-section or some othersuitable shape that is capable of minimal binding with mating channelkey 46. Channel key 46, as shown in FIG. 10, must have substantially thesame shape as channel slide 45, but in reverse so that it matinglyengages with channel slide 45. The fit between channel slide 45 andchannel key 46 may vary from relatively loose to tight, depending uponthe material from which each is fabricated. Generally, channel slide 45and channel key 46 clearance may close if the material for both channelslide 45 and channel key 46 are fabricated of a plastic such aspolycarbonate and polypropylene, as previously disclosed in this writtendescription. Lock 5 of upper piston segment 13 is shown inside barrel 2in a fully depressed position seated in lock depression space 12,thereby allowing upper piston segment 13 to slide within barrel 2.Nozzle 20 or distal end of needle 6 is out of its protective needlereceptacle 4 portion of barrel 2 and piston 3 combination. Needle 6penetrated seal 48 on its excursion through luer needle guide 24 andthen continued on through end cap needle guide 40. Support plate plug 35is extended into and mated with support plate plug cavity 47, therebyassisting the centering of needle 6 in luer needle guide 24 and end capneedle guide 40. Support plate 29 freely rides in barrel 2 since it hasa diameter substantially equal to the inside diameter of barrel 6,providing a slidable but tight fit between support plate 29 and barrel2. Support plate 29 is forced distally by upper faceplate segment 31when piston 3 is moved distally. FIGS. 1 and 2 show the relationship ofpush rod 26 and needle bore 22. In FIG. 1, push rod 26 extends into bore22 up to the proximal end of implant 11.

[0032] Push rod 26 need not extend to implant 11, but by doing so itprovides an efficient method of loading implant 11 into needle bore 22during manufacture of hypodermic device 1. During manufacture, implant11 can be inserted into needle bore 22 at the proximal end and thensupport plate 29, needle 6, and implant 11 combination inserted intobarrel 2 from the proximal end. Next, upper and lower piston segments 13and 14 are inserted into barrel 2 and pressed towards the distal end ofhypodermic device 1 until they are stopped from further movement bytheir respective locks 5. Since push rod 26 is in axial alignment withneedle bore 22, push rod 26 is automatically inserted into needle bore22 as support plate 29, needle 6, and implant 11 combination is moved ina direction from the proximal end of device 1 to the distal end bymovement of upper and lower piston segments 13 and 14 in that direction.In FIG. 1, push rod 26 is shown inserted into needle 6 and adjacentimplant 11. FIG. 1 also illustrates that push rod 26 partially residesin channel slide 45 along a portion of its longitudinal length extendingfrom lower face plate segment 32 to upper face plate segment 31. This isnecessary because, as shown, both upper and lower piston segments 13 and14 are cross-sectionally equal; yet push rod 26 (which is mounted onlower piston segment 14) must be axially aligned with needle bore 22 andbarrel 2. Push rod 26 is affixed to lower face plate segment 32 by pushrod taper 27, which allows for easy break-away or bending as will bedescribed in connection with FIG. 4. The length of lower piston segment14 is shorter than that of upper piston segment 13. And, as illustratedin FIG. 1, the resulting offset 53 between lower and upper pistonsegments 14 and 13 is positioned at the distal end of the two pistonsegments and not at their proximal end, so that lower face plate segment32 is more proximal than that of upper face plate segment 31. The offset53 is maintained at the distal end of the piston segments 14 and 13 byinterlocking stop 54 and stop tab 55 in pistol grip 7, which is mosteasily observed in FIG. 3. Stop 54 and stop tab 55 in effect preset thelocation of offset 53 at the distal end of piston 3 by halting thetravel of lower piston segment 14 relative to upper piston segment 13since the distance that stop tab 55 can travel before its movement ishalted by stop 54 is equal to the length of travel channel 56 (see FIG.8A), which in turn is equal to the distance that lower and upper pistonsegments 14 and 13 are offset 53.

[0033]FIG. 2 illustrates implant device 1 in the first of threesequences of operation. In FIG. 2, needle 6 has been extended outside ofneedle receptacle 4, its protective sheaf. Pushing upper piston segment13 in the distal direction as far as it will move extends needle 6.Prior to injection of implant 11, lock 5 on upper piston segment 13 hadto be depressed as described in connection with FIG. 1. Movement ofupper piston segment 13 is stopped when support plate 29 is adjacent thedistal end of needle receptacle 4. In that position, push rod 26 hasbeen extracted from needle bore 22. However, push rod 26 remains insupport plate guide way 57 (See FIG. 6) for easy re-entry into needle 6through needle inlet 21 due to the angled walls of guide way 57 towardsneedle inlet 21. Implant 11 remains in needle bore 22 at this stage ofoperation. Prior to pushing upper piston segment 13 distally, lock 5must be depressed to allow segment 13 to travel into barrel 2. Duringdistal movement of upper piston segment 13, its channel slide 45traveled along channel key 46 allowing for smooth, low frictionmovement.

[0034]FIG. 3 illustrates hypodermic device 1 after injection of implant11. Lower piston segment 14 has been moved distally so that stop tab 55is up against stop 54 retarding further movement. Further movement isalso retarded by movement of lower faceplate segment 32 against thedistal end of barrel 2. In this position, offset 53 between upper andlower faceplate segments 31 and 32 no longer exists as the offset nowexists at the proximal end of piston 3. Distal movement of lower pistonsegment 14 caused movement of push rod 26 into needle bore 22. Sinceoffset 53 is now absent at the distal end of piston 3, push rod 26 isable to travel further into needle 6 than it could in the position shownin FIG. 1 by the length of offset 53. The added length of penetration ofpush rod 26 causes implant 11 to be ejected out of needle nozzle 20 andinto the patient, other subject, or object. FIG. 3 also illustrates thatupper and lower face plate segments 31 and 32 and support plate 29 arenow in an abutting relationship, whereas in FIGS. 1 and 2 there wasspace between them. That space was maintained by the force of preloadspring 42. In the position shown in FIG. 3, pre-load spring 42 willcause upper faceplate segment 31 to separate from support plate 29 oncethe user of device 1 releases force on piston 3. Release of the force,however, will not cause uniform separation between support plate 29 andthe combination of upper face plate segment 31 and lower face platesegment 32 because hook 30 on lower face plate segment 32 has engagedundercut 33 on the distal face of support plate 29. As will most oftenbe the case, the user will inject implant 11 and then immediatelyproceed to retract piston 3.

[0035]FIG. 4 illustrates implant device 1 in its final state of use andready for disposal. In this position, needle 6 is fully retracted fromsupport plate plug cavity 47 into the safety of needle receptacle 4 bythe user's retraction of upper piston segment 13, which causes lowerpiston segment 14 to also retract due to the interaction of stop 54 andstop tab 55. As mentioned in the previous paragraph, when the distallydriven force on piston 3 is relieved, pre-load spring 42 will cause theupper portion of support plate 29 to tilt within needle receptacle 4 dueto engagement, during the injection phase illustrated in FIG. 3, ofundercut 33 by hook 40. Since there is nothing supporting the distal endof needle 6 at this point, it falls down into needle receptacle 4 whereit can no longer be extended outside barrel 2. Implant device 1 is nolonger usable and is ready for disposal with needle 6 already in asharps container-needle receptacle 4—protecting living beings orproperty from damage caused by sharp needle 6.

[0036] During the injection phase, resilient hook 30 is forced to rideup on ramp 52 (shown in FIG. 6) of support plate 29 to the point whereit reaches undercut 33, at which point resilient hook 30 snaps intoundercut 33 and engages the lower portion of support plate 29. Upon fullretraction of needle 6 into needle receptacle 4, the force of pre-loadspring 42 forces supports plate 29 to tilt at tilt angle 34. Tilt angle34 in one embodiment approximates 10 degrees. Tilting of support plate29 is also assisted by the differential friction between the upperportion of circumferential rim 60 of support plate 39 and barrel wall37. There is no friction between the lower portion of circumferentialrim 60 of support plate 39 and barrel wall 37 in the region of undercut42 because undercut 42 is located on a chord 58 of support plate 39 andchord 58 does not contact barrel wall 37. Chord 58 is best illustratedin FIGS. 8A, 8B, 9C, and 10C. The location of chord 58 in barrel 2,shown in FIGS. 1 through 5, is located towards the bottom of each of thefigures. Therefore, that area exerts the least frictional force andtipping occurs elsewhere with hook 40 and undercut 42 acting as thefulcrum.

[0037] Little resistance to this tilting force is encountered from pushrod 26, which remains in needle bore 22, since it is connected to lowerface plate segment 32 by relatively thin push rod taper 27. The resultof the tilting action is that nozzle 20 end of needle 6 tilts against awall of barrel 2 and is restrained by distal end of barrel 2 fromentering support plate plug cavity 23 and being further extended outsideof needle receptacle 4 for further use. Even an active attempt to shakeneedle 6 into alignment with support plate plug cavity 23 will not bemet with success due to force of pre-load spring 42 maintaining needle 6in the position shown in FIG. 4. Retraction of piston 3 is accomplishedby exerting a force directed in the proximal direction on either upperand lower piston segments 13 and 14 or only upper piston segment 13. Ineither case as the piston segments are pulled proximally, stop 54 willengage stop tab 55 and cause lower piston segment 14 to ride along. Uponretraction of piston 3, support plate 39 is pulled along with piston 3in the proximal direction by hook 40 on faceplate 41.

[0038]FIG. 5 illustrates an example of simple instructions marked on theproximal end of piston grip 7.

[0039]FIGS. 6 and 7 illustrate more clearly the details of support plate29 and needle 6 combination. Undercut 33 is along chord 51 of supportplate 35 as is ramp 52. Hook 30 is clearly seen in FIG. 7 as engagedwith undercut 33 and as having an arcuate wall to conform to thediameter of barrel wall 37 with which it matingly engages and travelsagainst during movement of lower piston segment 14.

[0040]FIGS. 8A, 8C, and 8D illustrate the particular details of upperpiston segment 13 more clearly than possible in FIGS. 1 through 4. FIG.8B illustrates an alternative embodiment to pre-load spring 42. Pre-loadlever 58 is made of the same resilient plastic material, as previouslydescribed, as are the other elements of hypodermic implant device 1.Pre-load lever 58 is integrally molded into upper faceplate segment 31and is seated into pre-load lever seat 59 when compressed as shown inFIG. 3. Pre-load spring 42 and pre-load lever and 58 represent twoillustrated embodiments of a biasing means for tilting support plate 29,but any means that accomplishes the function of tilting support plate 29is contemplated by this invention. Such a means could include no biasingmethod other than the frictional force between the upper portion ofsupport plate 29 and barrel wall 37 coupled with engagement of hook 30.FIGS. 9, 10A, 10B, and 10C illustrate the particular details of thebarrel 2 and lower piston segment 14 more clearly than possible in FIGS.1 through 4. FIG. 11 illustrates the general assembly of implant device1.

[0041] This “Detailed Description And Operation Of The Invention”section describes the invention configured for implantation into humansand animals for purposes of illustration. It is to be understood thatthis invention may be used for myriad other applications. One skilled inthe art can make changes in structure, material, and arrangement ofstructures without departing from the invention.

1-11. (Canceled)
 12. A hypodermic implant device, comprising: (a) abarrel comprising an open end and an inner end each in axial alignmentwith a central axis; (b) a piston, comprising an upper piston segmentand a lower piston segment, matingly engaged with an inner wall forsliding movement in the barrel; (c) a central axis aligned needlecomprising an inlet end, a nozzel end, and a means for guiding thenozzel out of the barrel upon distal movement of the upper pistonsegment; and (d) a lower piston segment push rod aligned with the needlebore for distal movement within the bore upon distal movement of thelower piston segment.
 13. The hypodermic implant device of claim 12,further comprising: (a) a needle receptacle and (b) a means forengagement of the needle to at least one piston segment, so that uponretraction of the at least one piston segment, the nozzel is fullyretracted into the needle receptacle.
 14. The hypodermic implant deviceof claim 13, further comprising a means for tilting the needle upon itsretraction into the needle receptacle.